What is this about?Edit
While petrification transforms the victim into stone, and freezing coats/turns the victim into ice, glass transformation could be seen as a combination of both.
As mentioned above, the victim who undergoes this type transformation will have its body crystalized into a figurine of glass, causing all transformed parts of the victim to lose its colour, while giving it properties such as transparency, light reflection/refraction and obviously, fragility.
Usually, life-sized glass statues function more or less the same like other statues as decoration items. Glass statues are rarely used for their material purposes, such as being a mirror.
Note : Victims whose bodies are trapped inside a panel of glass or a mirror and are transformed into a image/portrait/reflection depicting the captured victims are not considered to have been turned into glass. This type of transformation would be categorized as 'Flattened' similar to how victims can be turned into a painting, or become a part of the stained glass.
How about the Victim?Edit
Glass material, in itself, is usually transparent, and can reflect/refract light to a certain degree. That being said, victims who are transformed into glass possesses these traits as well. As a result, they are usually kept in mildly/strongly lit places where the statues may fully demonstrate the newly-given properties, highlighting their body features to their owners.
Given the fragile nature of the material, glass statues are sometimes shrunk to the size of a figurine, making it easier to display, move and store them as the owner pleases, while reducing the risk of breaking the statues by accident.
On a more uncommon case, victims who undergo this type of transformation will not inherit the transparent properties of the material... rather, they will be allowed to keep their original looks, retaining the colour of their attire and skin tone as paint on their glass bodies. The sub-type of this transformation would be called 'Painted Glass' (not to be confused with 'Stained Glass').